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How do I drill a hole in a coin? Sounds silly, but I want to do it right!

#1 User is offline   adenium 

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Posted 22 October 2009 - 07:48 AM

How do I drill a hole in a coin and not ruin the coin? I purchased three commemorative coins from a shop in Emmetsburg, IA. These are basically St. Patrick's day coins of little value to anyone outside of Emmetsburg. I want to drill a hole in each, attach a Travel Bug tag and release (I know this is the Geocoin forum, but I figured this would be the area to bring up drills and all things drilly).

It seemed like a simple plan until I drilled a test hole on a penny. I purchased a couple of titanium drill bits and got to work on my penny. After about five minutes I had a nice smooth divit drilled into the penny, but not a hole. After another five minutes, I had a hole of sorts. The exit hole was completely mangled. My question is, how do I do it right? I want a nice clean bore hole through the coin, without burs or a bulge around the exit hole. Is that even possible, given the limitations of a simple home workshop?

Thanks in advance,

Jason a.k.a. Adenium

#2 User is offline   Droo 

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Posted 22 October 2009 - 07:55 AM

View Postadenium, on Oct 22 2009, 08:48 AM, said:

How do I drill a hole in a coin and not ruin the coin? I purchased three commemorative coins from a shop in Emmetsburg, IA. These are basically St. Patrick's day coins of little value to anyone outside of Emmetsburg. I want to drill a hole in each, attach a Travel Bug tag and release (I know this is the Geocoin forum, but I figured this would be the area to bring up drills and all things drilly).

It seemed like a simple plan until I drilled a test hole on a penny. I purchased a couple of titanium drill bits and got to work on my penny. After about five minutes I had a nice smooth divit drilled into the penny, but not a hole. After another five minutes, I had a hole of sorts. The exit hole was completely mangled. My question is, how do I do it right? I want a nice clean bore hole through the coin, without burs or a bulge around the exit hole. Is that even possible, given the limitations of a simple home workshop?

Thanks in advance,

Jason a.k.a. Adenium

I've used a drop of oil to help keep the bit cool and always start with the smallest bit you can fit to your drill then expand to size you need. First hole shouldn't take but 10-15 seconds.
Oh, to avoid burrs on the backside - stop before drill goes all the way through, a little is okay to locate hole, and finish drilling from other side to remove burrs.

This post has been edited by Droo: 22 October 2009 - 08:01 AM


#3 User is offline   Renegade Knight 

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Posted 22 October 2009 - 08:03 AM

View Postadenium, on Oct 22 2009, 09:48 AM, said:

How do I drill a hole in a coin and not ruin the coin? I purchased three commemorative coins from a shop in Emmetsburg, IA. These are basically St. Patrick's day coins of little value to anyone outside of Emmetsburg. I want to drill a hole in each, attach a Travel Bug tag and release (I know this is the Geocoin forum, but I figured this would be the area to bring up drills and all things drilly).

It seemed like a simple plan until I drilled a test hole on a penny. I purchased a couple of titanium drill bits and got to work on my penny. After about five minutes I had a nice smooth divit drilled into the penny, but not a hole. After another five minutes, I had a hole of sorts. The exit hole was completely mangled. My question is, how do I do it right? I want a nice clean bore hole through the coin, without burs or a bulge around the exit hole. Is that even possible, given the limitations of a simple home workshop?

Thanks in advance,

Jason a.k.a. Adenium


machine oil like Droo mentions will help. Also a penny is a soft metal so you should have chewed right through it in no time. You may be using the wrong kind of drill bit, or have the right bit but it's dull. The cheapest way to make commemerative coins would use Bronze as the base metal so they would be soft as well. Cupro-Nickel (what most Silver US coins are made out of, and what a fair chunkc of silver coins world wide are made out of) are harder but I don't know how much harder since I really haven't drilled any. Of the top of my head it shouldn't be that difficult.

Ignoring all that using a drill press and a method of holding your coin still will give you the best result. Plan B is a vice, and free hand. Not as clean of a hole but better than freehanding it.

#4 User is offline   ATMouse 

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Posted 22 October 2009 - 10:34 AM

Drill press - it is the only way to go. And you will avoid a slip that might damage your hand forever.

#5 User is offline   bramasoleiowa 

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Posted 22 October 2009 - 10:46 AM

I'm assuming the coins are made out of brass or copper. If you have a metal punch, use that to help start the hole, then its quick drilling.

#6 User is offline   Six Little Spookies 

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Posted 22 October 2009 - 11:00 AM

If you have no drill press then tape the coin to a board. Use masking or duct tape, not scotch tape, but check to make sure it won't leave gummy bits all over the coin. Then clamp the board down (or stand on it) and go slowly. (make the hole slowly, the drill should be spinning as fast as it can!) Starting out with a small bit and working up from there is also a good idea.

#7 User is offline   Gitchee-Gummee 

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Posted 22 October 2009 - 12:12 PM

And do not forget the oil. If you are standing on the coin...... it's gonna melt your sole if you aren't lubing the drill bit.

#8 User is offline   WRITE SHOP ROBERT 

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Posted 22 October 2009 - 01:02 PM

After I get my hole drilled, I use the next sized bit to touch up the edges of the hole(Remove burs, and give the inside edge a tiny bevel, so there are no sharp edges to wear on the cable)

You can use Vice grips to clamp the coin down to a piece of scrap wood while you drill. Just protect the face from gouges.

#9 User is offline   Droo 

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Posted 22 October 2009 - 01:55 PM

And remember.... any gouges to your coin makes it less collectable and desirable for thieves while a gouge to your hand/foot does nobody any good.

This post has been edited by Droo: 22 October 2009 - 01:55 PM


#10 User is offline   Zork V 

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Posted 22 October 2009 - 02:29 PM

A drill press, hold the coin to base with quick clamps. I have drilled some geocoins and they are very hard, so take your time. Finish off with a countersink bit.

#11 User is offline   Mauison 

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Posted 22 October 2009 - 02:46 PM

Also, if there try to drill where there is only metal, no enamel, especially hard enamel, which may chip.

And if you do send these out to travel, they'll get scraped up anyway, banging around in those ammo cans.

#12 User is offline   dakin55 

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Posted 22 October 2009 - 03:28 PM

If you do not use " enough" pressure you can dull the drill bit as well. place it on a piece of wood to reduce buring and if it took you that long to drill a hole in a penny ( not that you would deface currency) put the drill in forward. sorry couldn't resist

#13 User is offline   Contra1971 

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Posted 22 October 2009 - 03:38 PM

all the advise they give is great, and will work well, but I wouldn't drill into any US coins as it is illegal
unles the government has deemed them no longer acceptable for circulation

This post has been edited by Contra1971: 22 October 2009 - 03:39 PM


#14 User is offline   Droo 

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Posted 22 October 2009 - 04:33 PM

View PostContra1971, on Oct 22 2009, 04:38 PM, said:

all the advise they give is great, and will work well, but I wouldn't drill into any US coins as it is illegal
unles the government has deemed them no longer acceptable for circulation

Somehow I don't see the Feds getting worked up about a single solitary holy penny. :o :)

Edit to add: Of course if you shine a light and the shadow of Mary, Joseph and Baby Jesus comes through the other side it's a totally different story!!

This post has been edited by Droo: 22 October 2009 - 04:36 PM


#15 User is offline   Contra1971 

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Posted 22 October 2009 - 05:18 PM

agreed, but it is still against the law, so why temp the powers?...lol

#16 User is offline   Gitchee-Gummee 

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Posted 22 October 2009 - 06:42 PM

View PostContra1971, on Oct 22 2009, 05:18 PM, said:

agreed, but it is still against the law, so why temp the powers?...lol



OMG!!!!!!! All those Lincoln cents that I put on the rail tracks. Wot am I tooooo doooo!

#17 User is offline   Gitchee-Gummee 

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Posted 22 October 2009 - 06:52 PM

Actually, if you want to drill a hole through an original DoubleEagle.......... I think only a few would care, and it wouldn't be the gov't.

#18 User is offline   Minimike2 

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Posted 23 October 2009 - 12:11 AM

Tape it to a paper plate, back off 100 meters and drill it with a .17 WCF.

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